How to serve non html content from a UI?

Is it possible to serve non-html content from a UI?

public class ObjectResource extends UI {

    public static class Servlet extends VaadinServlet { }

    @Override
    public void init(VaadinRequest request) {
        VaadinService.currentResponse.setContentType("someother/mimetype");
        response.getWriter().append("my content");
    }}

This clearly doesn't work. I can get the kind of output behaviour I want by using a ContentHandler, however not I've worked out how to utilise that functionality directly so that it fires when the app is fire run, rather than in a subsequent request.

Is this possible?

The reason I need something like this, is that I want to support an end point that serves content to an external browser which doesn't support java script. The main app sets up some content (backed by a database), and the slave browser can consume it with a single HTTP request.

Any pointers would be gratefully received.

Cheers,
Joe

It turns out to be possible, through the use of a global RequestHandler:

public static class Servlet extends VaadinServlet {
  @Override
  protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    getService().addSessionInitListener(new SessionInitListener() {
      @Override
      public void sessionInit(SessionInitEvent event) throws ServiceException {
        event.getSession().addRequestHandler(makeGlobalRequestHandler())
      }
    });
    super.service(request, response)
  }
}

The request handler is then available to handler the same request, and bypass the normal vaadin application handling if so desired:

equestHandler globalRequestHandler() {
  return new RequestHandler() {
    @Override
    public boolean handleRequest(VaadinSession session, VaadinRequest vaadinRequest, VaadinResponse response) {
      if ("/staticResource".equals(vaadinRequest.getPathInfo())) {
        response.setContentType("application/some-mimetype")
        response.getWriter().append("some content")
        return true
      } else
        return false
    }
  }
}